[Mobile Payments] The display stays awake after a software update until the user taps `OK` on the `Software updated` screen

[joshheald]

Context: pdfdoF-5yR-p2#comment-6593

1. Start a card reader software update by connecting the reader
2. Wait for it to complete without touching the phone
3. Observe that the device stays awake even when the update is complete

Expected behaviour

After the Software updated screen shows, the sleep timer should be re-enabled and the device display should go to sleep after the time elapses.

I've checked and we do call the isIdleTimerDisabled as soon as the update is complete. My total guess is that it doesn't start a sleep countdown until there's touches on the screen. I can't find anything to back that up, so it's just a hunch. I've only tested with the simulated reader though. If that's the case, we probably can't fix it.